1. Field of the Invention
The present invention relates to a fault diagnosis apparatus which diagnoses failures or faulty operations of a drive mechanism section used in office equipment, such as a copier, a printer, a facsimile, or a multifunction device having the features of these devices in combination, or in other equipment (e.g., an electrical household appliance, an automobile, or the like).
2. Description of the Related Art
In recent years, high productivity is required of various types of machines, particularly office equipment such as copiers or printers. Therefore, a long delay due to failure is not tolerated, and quick detection and solution of failures is sought.
Other industrial equipment, such as automobiles, aircraft, robots, and semiconductor design systems, are equipped, as means for operation control, with a plurality of highly reliable components which can operate at his speed with high accuracy. However, failures in a driving component, such as a motor or a solenoid, or in a mechanism element which operates in conjunction with the driving component, such as a drive circuit for driving a motor or the like, generally arise more frequently than do failures in electronic parts [passive electronic parts such as resistors and capacitors, transistors, or ICs (Integrated Circuits)]. In particularly adverse environments, various anomalies or failures that are difficult to detect arise even when a device is used in accordance with a conventional method. Recovery from the anomalies or failures involves consumption of much time and effort.
For these reasons, various systems (self-diagnostics systems) for detecting failures through self-diagnosis have been proposed. Such a self-diagnostics system monitors, for instance, a signal acquired during operation of a device and compares the thus-monitored signal with another signal (an expected value) which has been acquired beforehand in normal times and stored in memory, thereby diagnosing occurrence/nonoccurrence of a failure and specifying a location of any failure. A copier or a printer is equipped with driving compornents, such as a motor, a solenoid, and a clutch. The self-diagnostics system detects operating currents flowing through these driving compornents, and uses the thus-detected current value to diagnose anomalies in individual drive components or anomalies in circuits.